[en] The author gives a method for the evaluation of radiation doses, that the medical personnel have on the fingers and whole-body during medical radiographies, with a thermoluminescent dosemeter. The author explains for which reasons, he chooses this device. He gives also, the values of dosimetric measurements that he has obtained on personnel

[en] In the Cluff Lake-Carswell area (North Saskatchewan, (Canada)), characterized by particularly difficult conditions for unanium exploration, a project was developped on the use of polymetallic geochemical prospection in glaciated areas. Trenching and drilling allowed to obtain a three-dimensional picture of elemental dispersion and to estimate its pattern and complexity. The main results are: - the interest of polymetallic geochemical prospecting even for uranium; - the interest of lead in the case of rich deposits has been confirmed; - sampling difficulties, have been outlined; - powerful analytical facilities were shown to be a must; - airborne radiometric anomalies have been observed to be present in areas that show geochemical anomalies in the fine, less than 80 mesh, fraction, and not be present when the surveyed areas contain mineralized boulders that occur without smaller geochemically differentiated fragments; - the nature of dispersions observed in detailed exploration works is mechanical and more or less residual; - polymetallic geochemical methods are competitive: and elements such as B, As, Au, Pb and P have been selected as usuable local indicators; - geochemistry has been shown to be effective compared to radiometric methods

[en] Five antibody populations selected by immunoaffinity chromatography for the specificity toward various regions of toxin II of the scorpion Androctonus australis Hector were used to probe the interaction of this protein with its receptor site on the sodium channel. These studies indicate that two antigenic sites, one located around the disulfide bridge 12-63 and one encompassing residues 50-59, are involved in the molecular mechanisms of toxicity neutralization. Fab fragments specific to the region around disulfide bridge 12-63 inhibit binding of the ¹²⁵I-labeled toxin to its receptor site. Also, these two antigenic regions are inaccessible to the antibodies when the toxin is bound to its receptor site. In contrast, the two other antigenic sites encompassing the only α-helix region (residues 23-32) and a β-turn structure (residues 32-35) are accessible to the respective antibodies when the toxin is bound to its receptor. Together, these data support the recent proposal that a region made of residues that are conserved in the scorpion toxin family is involved in the binding of the toxin to the receptor

[en] Resonant lidar detection of iron atoms have been performed at the Observatoire de Haute Provence (France) during 4 nights in November 1986 and in April 1987. The average iron atoms abundance is 3.6 x 10⁹ cm^-2 in November, and 2.6 x 10^9- cm^-2 in April. Iron atoms density profiles are compared to the atomic sodium ones, obtained simultaneously by lidar and indicating an average sodium abundance of 4 x 10⁹ cm^-2. The relative abundance of the sum of the atomic and ionic forms is compared for several metallic species with their abundance ratios in the incoming meteorites. Finally, similar comparisons using lidar and mass spectrometer data are made for the ratio of the atomic and the ionic forms in the atmosphere

[en] The injection into the stratosphere of large quantities of sulfur during the June 1991 eruption of Mount Pinatube (Philippines) and the subsequent formation of sulfate aerosol particles have generated a number of perturbations in the atmosphere with potential effects on the Earth's climate. Changes in the solar and infrared radiation budget caused by the eruption should produce a cooling of the troposphere and a warming of the lower stratosphere. These changes could affect atmospheric circulation. In addition, heterogeneous chemical reactions on the surface of sulfate aerosol particles render the ozone molecules more vulnerable to atmospheric chlorine and hence to man-made chlorofluorocarbons

[en] Two antibody subpopulations directed against Anemonia sulcata toxin I or II have been purified by immunoaffinity chromatography. These antibodies are specific for a single antigenic region and were used in a structure-antigenicity relationship study using homologous toxins and chemically modified derivatives of A. sulcata toxin II. Asp-7 and/or Asp=9 and Gln-47 of toxin II were found to be implicated in the antigenic region recognized by the two antibody subpopulations. On the contrary, Arg-14, Lys-35, -36, and -46, and α-NH₂ of the glycine residue of A. sulcata toxin II are not involved in the corresponding antigenic region. When assayed for interaction with the sodium channel, the antigenic region of toxin II, including Asp-9 and Gln-47, appeared fully accessible to its specific antibodies, suggesting that it is not involved in the binding of the toxin to its receptor

[en] A general model has been developed to simulate the variations of the alkali metals (sodium, potassium and lithium) as measured by lidar soundings and photometric observations at various temporal -i.e. seasonal and diurnal- and spatial scales. In this paper, the first of a series of three, the general frame of a flux model of the metallic compounds is defined, emphasizing both the role of the meteoric input source and of the long term changes of the clustering processes which act like a sink for the metallic species by producing ionic hydrates. A detailed analysis of the ionic clustering reactions is presented which includes the influence of the buffer gas, the temperature and the nature of the ion and ligand molecules. Using the so determined reaction rates, the clustering chains of the various alkalis are then compared introducing a first differentiation between them. Furthermore, the introduction of ionic species also leads to taking into account the dynamical processes induced by the Laplace force which subsequently influence the behaviour of the neutral species. Indications of experimental confirmation of this modeling are discussed to introduce the model computations presented in the following papers

[en] An azidonitrophenylaminoacetyl mono[¹²⁵I]iodoapamin derivative was prepared which showed specific binding to rat neuronal membranes. UV photolysis lead to the irreversible occupation of binding sites. Photo- labeling of intact primary cultured rat neurons followed by membrane solubilization, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography revealed the covalent incorporation of radioactivity into 3 main components with Mr = 86,000, 30,000, and 23, 000. Labeling was completely prevented by a competing excess of native apamin. Similar studies on purified synaptic membranes from the rat brain showed another labeling pattern with major bands corresponding to Mr = 86,000 and 59,000. Although the reasons for the partial discrepancy between cultured embryonic neurons and an adult brain membrane fraction are not yet clear, the authors conclude that these proteins are intimately associated with the apamin binding site and are probably components of a type of Ca2+-activated K+ channel

[en] The linear stability of chains of magnetic vortices in a plasma is investigated analytically in two dimensions by means of a reduced fluid model assuming a strong guide field and accounting for equilibrium electron temperature anisotropy. The chain of magnetic vortices is modeled by means of the classical ‘cat’s eyes’ solutions and the linear stability is studied by analysing the second variation of a conserved functional, according to the energy-Casimir method. The stability analysis is carried out on the domain bounded by the separatrices of the vortices. Two cases are considered, corresponding to a ratio between perpendicular equilibrium ion and electron temperature much greater or much less than unity, respectively. In the former case, equilibrium flows depend on an arbitrary function. Stability is attained if the equilibrium electron temperature anisotropy is bounded from above and from below, with the lower bound corresponding to the condition preventing the firehose instability. A further condition sets an upper limit to the amplitude of the vortices, for a given choice of the equilibrium flow. For cold ions, two sub-cases have to be considered. In the first one, equilibria correspond to those for which the velocity field is proportional to the local Alfvén velocity. Stability conditions imply: an upper limit on the amplitude of the flow, which automatically implies firehose stability, an upper bound on the electron temperature anisotropy and again an upper bound on the size of the vortices. The second sub-case refers to equilibrium electrostatic potentials which are not constant on magnetic flux surfaces and the resulting stability conditions correspond to those of the first sub-case in the absence of flow. (paper)

[en] As it is imperative for the damage evaluation of infrastructures to establish an efficient non-destructive testing (NDT), an acoustic emission (AE) tomography technique has been developed. Authors has been studying tomography techniques based on elastic-wave and acoustic emission (AE) to visualize the internal defects in concrete. In the result of AE tomography, it can reasonably be assumed that lower elastic-wave velocity corresponds to heavier deterioration. Thus, the AE tomography estimates wave velocity distribution, which is supposed to be decreased as the damage progresses, inside the reinforced concrete. The AE tomography combines an iterative AE source location algorithm with travel-time tomography to produce a 3D visualization of the elastic wave velocity. However, since the computation for the elastic wave ray-trace algorithm considering all potential detours of elastic waves takes up much time, and in the case that only a few AE signals are detected, AE tomography technique does not always work efficiently. In this paper, AE signals induced by random hammering and rain droplets, which provide elastic waves with a variety of frequency, on surface of RC deck are utilized as elastic waves’ excitations, and wave velocity and attenuation tomography assuming linear ray paths are performed in conjunction with AE source locations. Accordingly, random hammering lead to a hundred of AE events after in-situ measurement for a few minutes and rain-induced elastic waves also does to thousands of those as well for an hour. Consequently, the 3D tomography results show accurate and time-saving analysis, compared to the above-mentioned conventional AE tomography technique, for quantifying the damage of RC slab. (paper)